Norway-based NorWind Installer has contracted Ulstein Sea of Solutions and Ulstein Idea Equipment Solutions as its design partners for a new foundation installation vessel for the offshore wind industry.
The vessel is a customised version of the Deepwater Enabler design from Ulstein. DP-equipped, the vessel is designed for worldwide operations with a focus on pre-piling and jacket/tripod/transition piece installation for the offshore wind industry in North Europe. Using Ulstein's generic vessel platform, different deck layouts, based upon NorWind's installation experience on the Alpha Ventus wind-farm off Germany, have been developed for the various installation modes.
Designed for maximum efficiency and cost effectiveness, the vessel and features an 800-tonne heave-compensated offshore crane on the starboard side, while a pre-piling template can be located on a support structure at the stern. The vessel can carry four jackets, alternatively at least 24 piles or up to 12 transition pieces on the large open aft deck. The anti-heeling system has been designed in such a way that the main crane can revolve over 180 degrees with a full load in its main hook within five minutes.
When operating in the pre-piling mode, the pre-piling template is positioned on the seabed by the main crane, while a pile is picked up by a gantry crane, put in the upending frame on starboard side and upended. The main crane has been modified by Ulstein in such a way that it can first pick up the piling hammer with its main hook and then connect to the upended pile with its auxiliary hook. When the hammer is working on driving the pile into the seabed, the next pile is upended by the upending frame and made ready for crane lift out.
The large aft deck and AHC crane provide flexibility for serving alternative subsea and offshore markets in the future, which is further increased by two large holds suitable for carrousels located below main deck. A deck layout version of the vessel has also been developed for tidal turbine installations.
Voith Schneider propellers, rated 3,900kW each, will allow for a cruising speed of 13 knots and enhance the DP capabilities of the vessel. To minimise the environmental footprint, a NOx reduction system is installed in the exhaust lines.
